1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method therefor and, more particularly, to a semiconductor device having semiconductor elements with different characteristics mixedly incorporating and a manufacturing method therefor.
2. Description of the Related Art
Hitherto, as this type of semiconductor devices, there has been one, for example, in which an SOI layer is partly removed, and then a bulk device is deposited on an exposed Si substrate (refer to, for example, Patent Document 1, Japanese Unexamined Patent Application Publication No. H1-183145). There has been another one in which the surface of each semiconductor layer of a plurality of semiconductor layers provided through the intermediary of insulating films is exposed, and then an impurity is implanted through the exposed surface and diffused to form each semiconductor element (refer to, for example, Patent Document 2, Japanese Unexamined Patent Application Publication No. H2-105565). There has been yet another one in which an SIO layer is partly removed and a vertical power element serving as a bulk device is formed on an epitaxially grown Si on an exposed Si substrate (refer to, for example, Patent Document 3, Japanese Unexamined Patent Application Publication No. H6-334030).
However, according to the semiconductor devices disclosed in Patent Documents 1 and 2, large steps are produced between portions wherein semiconductor elements having different characteristics are formed, making it difficult to achieve microminiaturization from the aspects of uniformity of resists, control of contact depths, processability of wires, etc. The semiconductor device disclosed in Patent Document 3 includes a process involving partial thick-film epitaxial growth. Such partial epitaxial growth is difficult to control and not suited for microminiaturization, making the semiconductor device unsuited for mass production. Furthermore, an attempt to eliminate a step between semiconductor elements makes it impossible to uniquely determine the thickness of a film to be epitaxially grown. This makes it difficult to control the characteristics of a bulk device.